Electrocatalytic nanocarbon (EN) is a class of material receiving intense interest as a potential replacement for expensive, metal-based electrocatalysts for energy conversion and chemical production applications. The further development of EN will require an intricate knowledge of its catalytic behaviors, however, the true nature of their electrocatalytic activity remains elusive. This review highlights work that contributed valuable knowledge in the elucidation of EN catalytic mechanisms. Experimental evidence from spectroscopic studies and well-defined molecular models, along with the survey of computational studies, is summarized to document our current mechanistic understanding of EN-catalyzed oxygen, carbon dioxide and nitrogen electrochemistry. We hope this review will inspire future development of synthetic methods and in situ spectroscopic tools to make and study well-defined EN structures.

The electrochemical behavior of graphene nanoribbons deposited onto glassy carbon electrode using pi-stacking interactions was investigated. We illustrate here that strong electronic communication could be achieved with basal plane of glassy carbon using simple electrochemical treatment. File list (3) download file view on ChemRxiv Manuscript.pdf (762.42 KiB) download file view on ChemRxiv Supporting_Information.pdf (2.07 MiB) download file view on ChemRxiv Manuscript.docx (49.18 MiB)

Low discharge capacities resulting from electronically insulating Li2O2 film growth on carbon electrodes is a major impediment to Li-O2 battery commercialization. Redox mediation is an effective strategy to drive oxygen chemistry into solution, avoiding surface-mediated Li2O2 film growth and extending discharge lifetimes. However, to continue improving upon prior research, exploration of new classes of redox mediators and discovery of novel selection criteria is required. Herein, we report a new class of triarylmethyl cations which are effective at enhancing discharge capacities up to 26-fold. Surprisingly, we observe that redox mediators with more positive redox mediator reduction potentials, and thus more sluggish kinetics for reaction with oxygen, lead to larger discharge capacities because of their improved ability to suppress the surface-mediated reduction pathway. This result provides important structureproperty relationships for future improvements in redox-mediated O2/Li2O2 discharge capacities. To aid future redox mediator discovery, we applied a chronopotentiometry model to investigate the zones of redox mediator standard reduction potentials and concentrations needed to achieve efficient redox mediation at a given current density. This analysis is expected to guide future redox mediator exploration.